Peripartal Lipid Metabolism and Tissue Fatty Acid Composition in Holstein Cows Fed Supplemental Fat During the Dry Period
Douglas, Gary Neil
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https://hdl.handle.net/2142/83540
Description
Title
Peripartal Lipid Metabolism and Tissue Fatty Acid Composition in Holstein Cows Fed Supplemental Fat During the Dry Period
Author(s)
Douglas, Gary Neil
Issue Date
2002
Doctoral Committee Chair(s)
Drackley, James K.
Department of Study
Animal Sciences
Discipline
Animal Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Animal Physiology
Language
eng
Abstract
Our laboratory showed marked decreases in hepatic lipid accumulation at calving after attempting to add BCS by feeding fat to dry cows. Results were confounded; feeding supplemental fat to dry cows was associated with lower DMI and BCS loss. Consequently, 36 cows were fed high-grain or fat-supplemented diets to reassess the effects of feeding supplemental fat to dry cows on BCS gain and peripartal hepatic lipid accumulation. Another diet was fed to test the efficacy of adding fat to a high-grain diet without regard for caloric density. Peripartal concentrations of total lipid and triglycerides in liver were similar among treatments. Feeding supplemental fat to dry cows had no effect on peripartal hepatic lipid accumulation or performance. Subsequently, 47 cows were fed high-grain or fat-supplemented diets at either ad libitum or restricted (80% of NEL requirement; NRC, 1989) intakes during the dry period to determine the effects of source and amount of energy fed on peripartal hepatic lipid content and postpartum production. Restriction-feeding resulted in lower lipid accumulation in liver immediately postpartum; nutrient intakes during the dry period had more pronounced effects on peripartal lipid metabolism than did composition of the prepartum diet. The degree of saturation of acyl chains within cell membranes could impact cell function. The extent to which fatty acid composition could be altered in peripartal dairy cows is unclear. During the last 40 d before calving, 25 Holstein cows were fed a control diet (CA, CR) or diets supplemented with fat from a saturated fatty acid mixture (S) or soybean oil infused into the abomasum to avoid biohydrogenation (U) to provide 120% (CA, S, and U) or 80% (CR) of NEL requirements (NRC, 1989). Feeding U increased C18:2 and decreased C20:4 and C22:6 in hepatic phospholipids on d 1 postpartum; changes were reversed by d 21 after calving. Fatty acid composition can be altered during late gestation but the impact on metabolism and performance of peripartal dairy cows is unknown. More research is needed to better understand the influences of supplemental fat in dry period diets on peripartal hepatic lipid metabolism and postpartum performance in dairy cows.
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